The present invention relates to a remote controller for a biped robot.
Biped robots which attempts have been made in recent years to put to practical use by the applicant of the present application and others have two legs extending from an upper body. Like humans, the biped robot moves by making a walking action to lift and place the two legs. In the present specification, the xe2x80x9cmovementxe2x80x9d of the biped robot covers motion from one place to another and also turning in substantially the same position to change the direction of the robot, for example.
For moving a biped robot, it is the general practice to teach a control apparatus for controlling the robot according to an algorithm which determines the pattern of a walking action that the robot is going to make (an algorithm which determines what walking action is to made at which timing).
This process of teaching the control apparatus according to such an algorithm requires a lot of time and labor for carrying out the teaching sequence. According to the process, it is difficult to control the robot to make various walking actions freely.
One solution is to instruct the control apparatus in a desired walking action for the robot under remote control with a remote controller or the like.
Unlike industrial robots that are installed at site, biped robots are intrinsically susceptible to disturbances and tend to lose attitude stability. Therefore, it is necessary to construct a robot control system that is designed taking into account the attitude stability of the robot.
It is also known in the art that the walking action of a robot is controlled by a so-called master-slave system. However, a biped robot control apparatus based on such a master-slave system is large in scale and complex in structure because the operator itself is required to make an action which is identical to a walking action that the manipulating person wants the robot to make.
The present invention has been made in view of the above background. It is an object of the present invention to provide a remote controller of simple arrangement for remotely controlling a biped robot to move while taking into account the attitude stability of the biped robot.
To achieve the above object, there is provided in accordance with the present invention a remote controller for a biped robot which moves in a walking action by alternately lifting and placing two legs, characterized by comprising a manipulation unit having a manipulator lever shiftable to a plurality of manipulated positions, for outputting a signal representing a manipulated position of the manipulator lever, and control means for being supplied with output signal data from the manipulation unit, generating a motion command for determining motions of the legs for at least two steps of the walking action of the robot depending on the manipulated position of the manipulator lever which is represented by the supplied output signal data, and controlling motions of the legs based on the motion command.
According to the present invention, the control means generates motion commands for the legs of the robot depending on the manipulated position of the manipulator lever, and controls motions of the legs based on the motion command. Therefore, it is possible to enable the robot to make a plurality of types of patterns of walking actions (e.g., forward movement, turning, lateral walking, etc.) by manipulating the manipulator levers. Since the motion command is generated for at least two steps of the walking action of the robot, a walking action pattern for at least two steps of the robot can be indicated by the manipulated position of the manipulator lever of the manipulation unit. Thus, the control means can generate the motion command while keeping the center of gravity of the robot in a position appropriate for maintaining the stable attitude of the robot.
According to the present invention, therefore, it is possible to remotely control movement of the biped robot while taking into account the stability of the attitude of the robot.
According to the present invention, more specifically, the motion command for determining motions of the legs for at least two steps represents a desired gait for two steps which comprises a current time gait for determining motions of the legs from a two-leg support period in which both the legs are placed until a next two-leg support period, and a next time gait for determining motions of the legs from the next two-leg support period until a two-leg support period next to the next. Each time a two-leg support period is reached, said control means obtains a next time gait immediately prior to the dual support base as a current time gait, generates a new next time gait depending on the manipulated position of said two-leg support period manipulator lever, and sequentially adjusts at least the new next time gait depending on the manipulated position of the manipulator lever.
With the above arrangement, while moving the legs of the robot based on the current time gait from each two-leg support period to a next two-leg support period, the next time gait from the next two-leg support period until the two-leg support period next to the next two-leg support period is generated. When the motion of the legs of the robot based on the current time gait is completed and the next two-leg support period is reached, the next time gait generated immediately prior to the next two-leg support period becomes the current time gait from the next two-leg support period. By thus generating a current time gait and a next time gait as a desired gait for two steps, it is possible to cause the robot to make a walking action while avoiding an abrupt shifting of the center of gravity of the robot and reliably maintaining the stability of the attitude of the robot.
Preferably, according to the present invention, the manipulation unit has manipulator levers associated respectively with the legs of said robot, and said control means generates said motion command for determining a relative placed position and/or attitude of the free leg with respect to the supporting leg, depending on the manipulated position of the manipulator lever which is represented by said output signal data with respect to the manipulator lever corresponding to the free leg in said walking action.
With the above arrangement, depending on the manipulated position of the manipulator lever corresponding to one of the two legs of the robot, a motion of the one leg is determined when the robot walks one step with the one free leg (the one leg is lifted and placed), and depending on the manipulated position of the manipulator lever corresponding to the other leg, a motion of the other leg is determined when the robot walks one step with the other free leg (the other leg is lifted and placed). That is, it is possible to indicate, to the control means, motions of the legs for two steps of the walking action of the robot by manipulating the manipulator levers which correspond respectively to the legs. The control means can thus generate the motion command so as to match the manipulated positions of the manipulator levers, so that the matching between the manipulation of the manipulation unit and the actual walking action of the robot is increased.
Preferably, according to the present invention, said plurality of manipulated positions include a movement stopping manipulated position for stopping movement of said biped robot, and said control means selectively generates a motion command for causing said legs to make a stepping action and a motion command for keeping said legs in a placed state, depending on a predetermined condition, when said manipulator lever is shifted to said movement stopping manipulated position.
With the above arrangement, when the manipulator lever is shifted to the movement stopping manipulated position, the legs make a stepping action or are kept in the placed state without moving the robot. While in the stepping action, the robot can smoothly start moving in a walking action when the manipulator lever is shifted from the movement stopping manipulated position to another manipulated position. While the legs are kept in the placed state, the consumption of electric energy by the robot can be reduced.
The predetermined condition for determining whether the legs are to make a stepping action or to be kept in the placed state may be indicated to the control means by the operator, using a switch on the manipulation unit. Alternatively, for example, the residual capacity of an electric energy storage device for operating the robot may be monitored, and the control means may automatically select the predetermined condition depending on the monitored residual capacity.
Preferably, according to the present invention, said plurality of manipulated positions include a predetermined neutral manipulated position, and said control means comprises means for recognizing a displacement of said manipulator lever from said neutral manipulated position to other one of the manipulated positions and/or a time-dependent rate of change of the displacement, based on the output signal data from said manipulation unit, said control means generating said motion command to adjust a displacement or a moving speed of said biped robot depending on the recognized displacement and/or time-dependent rate of change of the displacement.
If the manipulated positions include the movement stopping manipulated position as described above, then the movement stopping manipulated position and the neutral manipulated position may be the same manipulated position.
With the above arrangement, by adjusting the displacement of the manipulator lever from the neutral manipulated position and the rate of change of the displacement (the moving speed of the manipulator), it is possible to adjust the displacement (stride) and the moving speed of the biped robot, thus increasing the manipulability of the robot with the manipulation unit.
Preferably, according to the present invention, the remote controller further has placing detecting means for detecting when at least one of the legs is placed from a lifted state and outputting a detected signal to said manipulation unit, said manipulation unit having indicating means for indicating the placing of said at least one of the legs depending on the detected signal.
With the above arrangement, the operator of the manipulation unit can recognize the timing of the placing of each of the legs of the robot based on an indication from the indicating means, and hence can properly manipulate the manipulator lever so as to match the actual motion of the robot.
Preferably, according to the present invention, furthermore, said control means is arranged to generate a plurality of different types of said motion commands with respect to at least some of said plurality of manipulated positions, said manipulation unit having manipulation mode designating means for selectively indicating the types of the motion commands to be generated by said control means, to said control means.
With the above arrangement, the manipulation mode designating means can change a plurality of types of patterns of the walking action of the robot depending on the manipulation of the manipulation unit. Therefore, the operator of the manipulation unit can manipulate the walking action of the robot according to a manipulation pattern (manipulation mode) of the manipulation unit which matches the operator""s preferences.
The plurality of manipulated positions include a manipulated position for moving the robot in the fore-and-aft direction, a manipulated position for moving the robot in the lateral direction, and a manipulated position for moving the robot in the rotational direction.